Abstract: In order to improve the luminous efficiency of light-emitting diode (LED), a metal grating was placed on the light emitting surface of LED. The theoretical analysis based on finite difference time domain method shows that the transmittance of metal grating to the wavelength of 460nm is close to 1 after the optimization of the grating, and the light extraction efficiency of LED can be improved. The optimized metal grating can simultaneously excite surface plasmons polariton and the localized surface plasmon at 460nm, which is helpful to improve the internal quantum efficiency of LED. The luminous efficiency of LED with metal grating structure at 460nm is 30 times higher than that of LED with only a thin layer of Ag on light-emitting surface. The research can provide theoretical guidance for the preparation of high luminous efficiency LED in the future.